The instant invention relates to medical devices which are implantable in the human body and more particularly to an implantable infusion port for dispensing medication in the body of a patient.
Infusion ports which are implantable in the bodies of patients for dispensing medications therein have been heretofore available and have been favorably accepted by the medical field for a number of years. In this connection, it has been found that implantable infusion ports can be effectively utilized for dispensing medications in the bodies of patients and that they are substantially more effective than catheters and the like for use over prolonged periods of time since they do not require permanent openings in the skin. The most common type of heretofore-available infusion port comprises a rubberized base portion, a metallic housing portion which is received on the base portion and has an open cavity formed therein which is accessible through a reduced entry passage in the upper end of the housing portion, a penetrable seal portion which is received in the entry passage in the housing portion, and a catheter element which extends from the open cavity to the exterior of the device. The housing portion is received in assembled relation with the base portion so that it cooperates therewith to define a truncated conical configuration in the infusion port and so that the entry passage is located in the upper end of the infusion port. Normally, a device of this type is surgically implanted in a patient so that it is positioned beneath the skin and so that the upper end of the housing portion and the penetrable seal face outwardly, and the catheter element of an infusion port of this type is normally installed so that it can transmit fluids from the cavity to a predetermined area of the patient's body, such as a large vein. Once an infusion port of this type has been installed in a patient, the cavity can be periodically filled with medication by inserting a hypodermic needle in the patient so that it penetrates the skin and passes through the penetrable seal portion of the device for injecting medication into the interior cavity therein. It has been found that an infusion port of this general type can be effectively utilized for dispensing medication in the body of a patient over a prolonged period of time and that it is generally preferable to a catheter or the like which would require a permanent opening in the skin, since it is substantially less likely to provide a sight for infection.
While the heretofore-available infusion ports have generally been found to be more effective than catheters and the like for introducing medications into the bodies of patients over prolonged periods of time, they have nevertheless had substantial disadvantages. Specifically, it has been found that because of the truncated conical configurations of most of the heretofore-available infusion ports, they have generally had cavities of relatively small dimension. Further, it has been found that when an infusion port includes a metallic housing having a reduced entry passage, it is sometimes difficult to locate the entry passage with the tip of a hypodermic needle when the infusion port is covered by the skin of the patient. In addition, it has been found that when the open cavity of an infusion port is defined by a metallic housing, it is possible for a hypodermic needle which is inserted into the housing to strike a wall of the housing and be damaged so that a barb is formed on the tip of the needle. When the needle is thereafter withdrawn from the infusion port, the barbed tip can cause damage to the penetrable seal portion of the infusion port, and it can also cause substantial trauma to the skin and tissue of the patient as it is withdrawn. Further, it has been found that even when a hypodermic needle is carefully inserted into an infusion port of this type so that a barb is not formed on the end of the needle, a certain amount of damage is caused to the seal portion of the infusion port; and since the entry passage has a relatively small penetration area, the relatively small seal portion can become severely damaged from needle penetrations in a relatively short period of time. Similarly, it has been found that since the entry passage of an infusion port of this type is relatively small, the needle injections which are periodically required to replenish the supply of medication in the cavity must be made through a very localized area of the patient's skin so that the skin in this area never has a chance to heal properly, and the same localized area of skin is repeatedly traumatized from adhesive tapes and antibacterial agents. In addition, it has been found that when a needle injection is made in a patient in order to introduce medication into an infusion port of this type, the needle must be positioned in substantially perpendicular relation to the skin so that bulky padded dressings are often required to provide support for the needle as the medication is introduced. Still further, it has been found that when an infusion port is made in a truncated conical configuration, it can produce an unattractive mound on the body of a patient which is likely to cause irritation when it is rubbed by clothing or when the mound is accidentally bumped or bruised; and the trauma which is caused by an accidental blow to the mound is greatly increased when an infusion port includes a metallic housing portion. In addition, it has been found that when an infusion port includes a metallic housing portion, fluoroscopic or X-ray examination of a hypodermic needle which is inserted into the infusion port is hampered by the housing portion, and that bodily fluids can migrate into seams and/or crevices in an infusion port of this type.
The instant invention provides an effective infusion port which overcomes the disadvantages of the heretofore-available infusion ports and which is operable with substantially increased effectiveness and substantially reduced patient trauma. The infusion port of the instant invention generally comprises a septum having a base portion, a side wall portion and a top wall portion which cooperate to define an enclosed cavity for receiving medication in the septum, and a catheter element which extends between the cavity and the exterior of the septum for dispensing medication in the body of a patient. At least a portion of the side wall portion of the septum is made of a material which is penetrable by a hypodermic needle for introducing medication into the cavity but which is substantially self-sealing upon removal of the needle therefrom. In the preferred embodiment, the septum is integrally formed from a nontoxic rubberized material, such as a silicone rubber, which is penetrable by a hypodermic needle but self-sealing upon removal of the needle, and the side wall and top wall portions of the septum are formed in a rounded dome-shaped configuration. The base portion is preferably formed so that it extends outwardly a distance around the periphery of the side wall portion to define a peripheral rim on the septum, and reinforcing means is preferably embedded in the rim to allow the infusion port to be secured in the body of a patient which sutures or the like. In one embodiment of the infusion port, a plurality of needle shields are embedded in the top wall, side wall, and base portions of the septum for guiding the tip of a hypodermic needle which is inserted through the side wall portion so that it passes into the cavity in the interior of the septum. In still another embodiment of the infusion port, a partition is provided in the septum for separating the cavity into first and second cavity sections or chambers, and first and second catheter elements are provided which extend between the first and second chambers and the exterior of the septum so that this embodiment of the infusion port can be utilized for administering two different medications in the body of a patient over a prolonged period of time.
Accordingly, it is seen that the infusion port of the instant invention has significant advantages over the heretofore-available infusion ports. Specifically, the septum of the infusion port of the instant invention has a substantially increased penetration area since it is adapted for side entry so that the cumulative effects of damage to the septum caused by needle penetrations are substantially reduced. Similarly, since the septum has an enlarged penetration area, the penetration area on the side of a patient is similarly increased so that the same localized area of the skin does not have to be penetrated each time a needle injection is made. In addition, since the infusion port of the instant invention is adapted to receive hypodermic needles through the side wall portion of the septum, a needle which has been inserted into the septum can be laid flat on the skin so that it does not need to be supported by bulky dressings and the like. In addition, because of the rounded dome-shaped configuration of the septum, the infusion port of the instant invention produces a substantially less offensive mound or raised area on the body of a patient in which it is installed; and because the infusion port is preferably integrally molded of a rubberized material, trauma to the patient is substantially reduced when the area adjacent the infusion port is accidentally bumped or bruised. Still further, because of the flexibility of the infusion port, when external forces are applied thereto they are more gently distributed to underlying and overlying tissue, and therefore less trauma is caused to the patient than would otherwise be caused by a conventional infusion port. Still further, since the infusion port of the instant invention does not include a metallic housing, hypodermic needles which have been inserted into the septum cannot become barbed and they can be effectively viewed through the use of X-ray and/or fluoroscopic equipment. Still further, since the septum of the infusion port preferably has a dome-shaped configuration and the cavity preferably has a cylindrical configuration, the side wall portions of the septum have increased thicknesses and this tends to stabilize a needle which has been inserted therethrough so that the needle can be left in the patient for a prolonged period of time if needed without causing severe trauma to the overlying subcutaneous tissue. Still further, since the infusion port of the instant invention is preferably integrally molded of a nontoxic rubberized material, it does not have crevices or seams into which bodily fluids could migrate.
Accordingly, it is a primary object of the instant invention to provide an improved infusion port for administering medication to a patient.
Another object of the instant invention is to provide a side-entry infusion port for administering medication to a patient.
An even further object of the instant invention is to provide an effective infusion port which is integrally molded of a nontoxic, rubberized material.
A still further object of the instant invention is to provide an infusion port having an increased entry area.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.